Trinuclear cyanine dyes



United States Patent 11 Claims. (Cl.260-'--240 1) This invention relates to cyanine dyes and to the production and use thereof. g

In accordance with the present invention'there are pro videdcyanine dyes of the general formula:

wherein R is an alkyl group or an aryl group, R is an alkyl group containing up to 6 carbon atoms and further containing a carboxylic acid, sulphonic acid, sulphuric acid, hydroxy, alkoxy, acyloxy, alkoxycarbonyl, cyano, amino, alkyl-substituted amino, or carbamoyl group, R is hydrogen or an alkyl group, R and R are each an alkyl, hydroxyalkyl or aralkyl group, 211 and n2 are each nought or one, m is nought or one, X is an acid radical, Y is hydrogen or an alkoxy group, and D and D are each the residue of a five-membere'd or siX-membered heterocyclic nitrogen nucleus, and corresponding dyes. of the said formula but in which the X radical and a hydrogen atom of a sulphonic, sulphuric or carboxylic group contained in R are eliminated, and corresponding acid addition salts of these dyes in which R, carries an amino group.

In the foregoing formula the alkyl groups are preferably 'methyl, ethyl, propyl or butyl, suitable hydroxyalkyl groups are B-hydroxyethyl, -y-hydroxypropyl and fi'y-dihydroxypropyl, and a suitable aralkyl group is benzyl.

D and D may each be the residue of any five-membered or six-'membered heterocyclic ring system including thiazoles, oxazoles, selenazoles and their polycyclic homologues such as those of the benzene and naphthalene series; pyridine and its polycyclic homologues, such asquinoline and ozand ,B-naphthoquinolines; indolenines; diazolesl (e.g. 1:3:4- thiadiazole); thiazolines; diazines' (e.gi pyrimidines and quinazolines). The polycyclic compounds .of the series may besubstituted in the carbocyclic ringswith one or more groups such asalkyl, aryl, alkoxy and methylene dioxy groups, or by halogen atoms.

X may be any acid radical, for example halide (chloride, bromide, iodide), sulphate, sulphamate, perchlorate or p-toluene sulphonate.

The foregoing compounds of Formula I and those in which HX has been eliminated are valuable sensitisers for photographic silver halide emulsions andmay be used in that connection in quantities similar to, and by methods similar to, those well known in the art for the 'sen'sitising of photographic emulsions with cyanine dyes.

ICC

According to a further feature 'of the invention the compounds of general Formula I areprepared by reacting a compound of general Formula II;

CSRs N in (II) with a compound of the general Formula, 111:

o= oH-oH nz' a R5 it 111) whereQ is athioether (SR), thioether vinyl P (CH=CHSR) or acetanilidovinyl group and R is an alkyl group containing up to-6 carbon atoms.

Instead of using a compound of Formula 111 there may be used a corresponding base together with a stoichiometric quantity of a quaternary salt R X.

The foregoing condensations aremost conveniently ef- R! with a compound of general Formula V:

\ l 7 a =(GH.CH)B1= 111/ \X (Y) (b) Reacting a compoundofgeneral Formula VI: D

l I (OH GH)n1=(' CHR4 Rr X (VI) witha compound of general Formula .VlI: y gi 0 s xfi p R1 (VII) and an orthoacetate of the Formula VIII:

7 CH --C(OR) r (VIII) R being an alkyl group of up to 6 carbon atoms and the othersymbols $3 (c) Reacting a compound of the Formula IX:

= oH-oH)..1=('J-o=o-or13 Y I where T is a thioether or substituted amino group, with a compound of general formula VII above, each of the foregoing steps being followed by treatment of the product with a quaternating agent R Z, where Z is a halogen atom, e.g. chlorine or bromine.

The following are illustrative procedures for the production of the products (referred to as primary intermediates) which, after quaternation with R Z as referred to above, yield the intermediates used in the production of the dyesofthe present invention:

PRIMARY INTERMEDIATES (A) 3-Methyl-2-[2-(1-Methyl-2-Thi0-3ind0linylidene)- Propylidene]-Benzothiazoline. (a) A mixture of 3-isopropylidene -'1-methylindolin-2- thione (0.96 g), 3-methyl 2-methylthiobenzothiazolium minutes. The solidwhich separated was filtered off and washed with hot ethanol. The product was identical with that obtained in (a) above.

(c) 3-methyl 2 thioacetylmethylenebenzothiazoline (2.2 g.) and methyl toluene-p-sul-phonate- (1.9 g.) were fused together on the steam bathfor 30 minutes. The

product was refluxed with 1-methylindolin-2-thione (1.6

g.) vin. ethanol. (10 ml.) containing triethylamine (1.5 ml.) for one hour, and the solid which separated was collected and washed with hot ethanol. The product was identical with that described in (a) above.

By similar methods the following merocyanines B-L may be prepared: 7 (B) 3-Ethyl-2-[2-(1-Methyl-2-Thio 3-lndolinylidene)- Propylidene] -Benz0thiaz0-line The compound formed green crystals, M.Pt. 235-237 (decomp.), by crystallisation from Z-methoxyethanol. c 3-Ethyl-2-[2-(1-Ezhyl 2-Thio-3 lmiolinylideney Propylid'ene]-Benz0thiaz0line The compound formed green crystals, M.Pt. 233-234", by crystallisation from 2-methoxyethanol. (D) 5-Chl0r0-3-Methyl-2 [2 (I-Methyl-Z-Thio-3-Indolinylidene-Propylidenel Benzothiaz0line The compound formed deep green crystals, M.Pt. 228- 229, by crystallisation from Z-methoxyethanol. (E) 5-Methoxy-3 MeIhyI-Z-[Z-(I Methyl'-2-Thi0"-3- Indolinylidene)Pr0pylidene]-Benz0thiaz0line The compound formed green crystals, M.Pt. 254-255",

. by crystallisation from 2-methoxyethanol.

(F) 6Meth0xy-3 Methyl-Z-[Z-(I Methyl-2-Thio-3- Indolinylidene) -Pr0pylidene] -Ben'zothia'zoline The compound formed deep' green crystals, M.Pt. 234- 235, by crystallisation from 2 -methoxyethanol. (G) 5,6-Dimethoxy-3 Methyl-2-[2-(1Methyl-2-Thi0-3- lndolinylidene -Pr0pylidene] -Benz0thiaz0line The compound formedbronze-coloured crystals, M.Pt. 267, by crystallisationfrom 2-methoxyethanol.

ing triet-hylamine' (0.3 ml.) for 30 minutes.

, 4 (H) 3-Ethyl-5,6-Dimethyoxy 2-[Z-(l-Methyl-Z-Thimli- I ndoliny lidene) -Pr0py lidene] -B enzothiazolinc The compound formed deep purple crystals, M.Pt. 235-236", by crystallisation from 2-methoxyethan0l.

1 3-2' Hydroxyethyl 2 [2-(1'-Methyl-2-Thio-3- Indoliny lidene -Pr0py lidene] -Benz0thiaz0lin e The compound formed deep purple crystals, M.Pt. 219- 222", by crystallisation from 2-methoxyethanol.

(J) 3,5 Dimethyl-Z-[Z-(I Methyl-2-Thi0-3-Ind0linylidene)Pr0pylidene] -Benz0selemlz0line The compound formed purple crystals, M.Pt. 274- 275, by crystallisation from pyridine.

(K) 3-Eihy l-5-Methy 1-2- [2- (I-Methy l-2-Th1'0-3- Indolinylidene) Propylidene -Benz0selenaz0line The compound formed green crystals, M.Pt. 242-243", by crystallisation from Z-methoxyethanol.

(L) 1 -Methyl-2- [2-(1 -Phenyl-2 T hi0-3-I ndolz'nylidene} Propylidene].-Benz0thiaz0*line- The compound formed purple crystals, M.Pt. 236- 238? by crystallisation from 2-methoxyethanol.

The quaternisationwoif the foregoing intermediates is i1.- lustrated in the examples which follow later herein.

The following examples, in which the temperatures are given in degrees centigrade, and in which the utility of the end products in the sensitising of photographic silver halide emulsions is given, Will serve to illustrate the invention:

EXAMPLE 1.-BIS (3 METHYL 2 BENZOTHIA- ZOLE) B-(Z-T-HYDROXYETHYLTHIO 1 METH- YL 3 INDOLYL) TRIMETHINCYANINE BRO- MIDE A mixtureof 3-methyl-2-[2-(l-methyl-2-thio-3-indolinylidene)-propy1idene]-benzothiazoline (0.60 g.), 2-bromoethanol (0.15 ml.) and chloroform (10 ml.) was refluxed for 21 hours. Evaporation of the solution and stirring the residue with dry ether gave a red powder. This was refluxed with 3-methyl-2-methylthiobenzothiazolium toluene p-sulphonate (0.60 g.) in ethanol (10 ml.) contain- The dye which separated was filtered off and was washed with cold ethanol. crystallisation from 2-methoxyethan0l gave the dye as green crystals, M. Pt. 287-288 (decomp.).

' The dye extends the sensitivity of a silver iodobromide photographic emulsion to 6550 A. with a maximum at 6400 A.

to dryness. The resulting solid was refluxed in ethanol ('10 nil.) with 5,6-dimethoxy 3- methyl- 2 -'me thylthiobenzothiazolium iodide (0.65 g.) and triethylamine (0.3 ml.) torso minutes. The, dye, which separated on cooli'ng'the solution, was filtered off and crystallised from methanol. It formed purple crystals, M. Pt. 211-212.

The dye extends the sensitivity of a silver iodobromide photographic emulsion to 6750A. with a maximum at EXAMPLE 3.-(3-METHYL 2 BENZOTHIAZOLE) (5 ,6-DIMETHOXY 3 METHYL 2-BENZOTHIA- ZOLE) [3- ('2-2'-CYANOETHYLTHIO l-METHYL-3- INDOLYL)-TRIMETHINCYANINE IODIDE Amixture of 5,6-dimethoxy-3-methyl-2-[2-(l-methyl-2- thio-3-indolinylidene) propylidene] benzothiazoline (0.7

was evaporated to dryness. The product was refluxed for 30 minutes in ethanol (20 ml.) with 3-methyl-2- -was evaporated under reduced pressure, and the residue ywaslrefluxed for one hour in ethanol (20 ml.) with 5,6-

dimethoxy 3 methyl 2 methylthiobenzothiazolium toluene-p-sulphonate (0.9 g.) and triethylamine (0.5 ml.).

5 methylthiobenzothiazolium toluene-p-sulphonate (0.8 g.) 5 Addition of aqueous potassium iodide ,solution caused the and triethylamine (0.3 ml). Addition of aqueous poseparation of the dye, which was obtained as deep purple tassium iodide solution caused the separation of the dye, crystals, Pt. 190-492", by crystallisation from methwhich was collected and crystallised from methanol, when anol. p p it formed deep purple crystals; M. Pt. 201-203; The dye extends the sensitivity of a silver iodobromide The'dye'extends the sensitivity of a silver iodobromide photographic emulsion to 6800 A. with a maximum at photographic emulsion to 6650 A. with a maximum at '6650 A. p

6450 A. 1 The dyes of Examples 6 to 23 were prepared by meth- OdS similar to thOSC described in Examples 1 to 5, the

i 2 results being collected in Table 1. In each case a meroa (2 HYDROXYETHYLTHIO 1 METHYL cyanlne (the letters given in the first column of the tahle refr t0 primary lntermechates Was reacted RATE a one of the following quater'nising agents: 3-etllyl i6-dimethoxy 2 [2-(1-methyl-2-thio-3-ind0- 2-bromoethanol V ,R =CH .CH OH linylidene)-propy1idene]-benzothiazoline (0.7 g.) and 2- 1-bromopropan 2-ol' '-CH .CH(OH)CH bromoethanol (0.15 ml.) were refluxed together in chloro- 3-iodopropan-lol CH .CH .CH '.OH

form ml.) for 15 hours. Evaporation of the solution 1,2-dihydroxy-3-iodopropane CH .CH(OH)CH OH gave a sticky solid, which was refluxed for 45 minutes in 2-ethoxyethyl bromide CH .CH .O.C H

. ethanol (25 ml.) with 3-ethyl-2-ethylthiobenzothiazolium 2-iodoethyl acetate CH .CI -I .O.CO.CH

toluene-p-sulphonate and triethylamine (0.3 ml.). Addi- Ethyl bromoacetate CH .CO C H tion of an aqueous solution of sodium perchlorate caused fi-Iodopropionamide j CH .CH .CONH the separation of the dye, which was obtained as purple fi-Bromopropionitrile -CH .CH .CN crystals, M. Pt. l47l49, by crystallisation from methanol. The resulting quaternary salt was reacted with an alkyl- The dye extends the sensitivity of a silver iodobromide thioheterocyclic quaternary salt to give the dye. All of photographic emulsion to 6450 A. with a maximum at the dyes in Table I possess the structure of general For- 6100 A. mula X:

EXAMPLE 5.-BIS-(5,6-DIMETHOXY-3-METHYL-2- r ,5 BENZOTHIAZOLE) B-(Z-Z-ETHOXYETHYLTHIO- l i i l-METHYL-3-INDOLYL) TRIMETHINCYANINE il IODIDE V 1 X R5 A mixture of 5,6-dimethoxy-3-methyl-2-[2-(l-methyl- SR3 2-thio-3-indolinylidene) propylidene] benzothiazoline V (0.7 g.), fl-ethoxyethyl bromide (0.3 g.) and 2-methoxya N ethanol (10 ml.) was refluxed for 2 /2 hours. The solvent X) t r 5 TABLE 1 i [The letter following the example number indicates the meroeyanine used. The anion of the salt obtained is indicated in the column of melting points] Seusitising A Example End Groups R3 M 50,

' Extent Max.

6A, 3-methyl-2-benzothiazole 5,tfiglimefhoxymethyhZ-benzo- QH2-CH2OH 22%;?26 6,650 6,500 7B 3-ethyl-2-benzothiazole 3-eth gl- 2 la enzothiazolefl; CH2.CO2Et 6,400 6,150 $10 5-methoxy-3-methyl-2-benzothia- 5-meithoxy-3-methyl-2-benzothia- -CHzCH20H ZB -Efi 6, 750- 6,600 9]? fighoxy-3-methyl-2-benzothiae esfiox -a-m6thy1-2-benzothia-' C Hr.CH 0H 22 230 6,500 6,300 10G 5,6 3liihethoxy-3-methyl-2-benzo- 3-rhet?hyl-2-benzothiazole CHz.CHz.CH2OH 20%;)211 6, 700 6,500 .11G i 1 1i) f -.66 CHz.C H(0H). Ha 21%215 6,700 2,388 "12G 66 dO CHZ.CH(OH).CH2OH 194 200 6,700 1 136 dO Q-- dO -om.cm00n15 19 02 6,600 61500 14G do d6 OH5.OHz0C0CHa... 16125168 6,550 6,450 15G do do CHZ-CHZ-CONHr 21am 6,500 6,100 10o dO 5,6-dimethoxy-3-methyl-2-benzo- CHz.CHzOH 266-267 7, 000 6, s00 thiazole. (I) 6 600 17G do (10 GH2.CH2.CH2OH 22%;)232 6,900 61800 18G do 4. do CHz.CH(OH).CH2OH-.- 2505252 6,500 19G do "66--., -CH2.CHz.OCOCHa 19 398 6,800 32 20G dO d0 OHz.CHz.CONH-r 2065208 6,900 21G 16 16 -oH2.cm.cN 19 200 7, 000 61750 22H 3-ethyl-5,6 dimethoxy-2benzo- 3-ethyl-5,6-dimethoxy-2-benzo- -CH2.CH2OH 203-205 6,650 6,300

thiazole. thiazole. (I) 23.1 3,5-dimethyl-2-benzoselenazole afifiigngggmxy-li-methyl-benzo- CH.CH2OH 22325224 6,700 6,550

' PHENYL t 'The following two Examples 24 and 25 were prepared EXAMPLE 24.,BIS 3 METHYL 2 BENZOTHI- photographic emulsion to 6550 A. with a maximum at EXAMPLE 25.-(3 METHYL 2 BENZOTHIA- ZOLE) (5,6 DIMETI-IOXY 3 METHYL 2 BEN- ZOTHIAZOLE) ,8 (2 2' HYDROXYETHYLTHIO- 1 PHENYL 3 INDOLYL) TRIMETHINCYA- NINE BROMIDE The dye formed green crystals, M. Pt. 225-226, by

crystallisation from methanol.

The dye extends the sensitivity of a silver .iodobromide photographic emulsion to 6650 A. with a maximum at EXAMPLE 26.BIS METHOXY 3 METHYL- 2 BENZOTHIAZOLE) B (2 2' DIETHYLAMINO- ETHYLTHIO l METHYL 3 INDOLYL) TRI- METHINCYANINE IODIDE A mixture of 5-methoxy-3-methyb2-[2-(l-methyl-2- thio 3- indolinylidene) propylidene] benzothiazoline ('0. 6 g.)- and B-diethylaminoethyl bromide hydrobromide (0.6 g.) was refluxed for 4 hours in chloroform (40 ml.) containing triethylamine (0.3 ml.). Evaporation of the solution left a' sticky yellow solid. This was refluxed for 45- minutes with 5-methoxy-3-methyl-2-methy1thiobenzothiazolium toluene-p-sulphonate (0.7 g.) in ethanol (15 ml.) containing triethylamine (0.4 ml.). Addition of aqueous potassium iodide solution caused the separation of the dye, which was obtained as deep purple crystals,

M. Pt. 186-189, by crystallisation from methanol.

requires C, 53.9; H, 5.4; I, 15.8%.)

The dye extends the sensitivity of a silver iodobromide photographic emulsion to 6750 A., with maxima at 6100 and 6600 A.

EXAMPLE 27. (3-METHYL-2-BENZOTHIAZOLE)- (5.6-DIMETHOXY-3-METHYL 2 BENZOTHIA- 'zoLamz 2' DIETHYLAMINOETHYLTI-IIO-l- METHYL 3 INDOLYL)-TRIMETHINCYANINE IODLDE HYDRIODIDE areaee 'sirnilarly from lvmethyl-2-[2-(1-phenyl-2-thio-3-indolinyl- 'idene -propylide ne] -benzothiazoline.

thia zolium toluene p-sulphonate (0.8 g.) and tn'ethylamine (0.3 ml). Additionxof-aqueous' potassium iodide solution caused the separation of the dye, which was filteredofi and crystallised from methanol, when it was photoguaphic obtained as bronze-coloured crystals, M. Pt. 271- 272' (deccnnpy (Found: C, 46.25; H, 5.0 I, 27.1.

v C H lN 0 S l-lLH O requires C, 46.5; H, 4:8;1, 27.3%.)

"Thedyeextends the sensitivity of a silver iodobromide emulsion to 6600 A. with a maximum at EXAMPLE 2*8. (3-METHYL-2-BENZOTHIAZOLE)- (1,3,3-TRIMETHYL-2-INDOLENINE),8 (2-2 HY- DROXYETHYLTHIO-l-PHENYL 3 -"INDOLYL)- PENTAMETHINCYANINE I ODIDE A mixture of 3-methyl-2-[2 -(l-phenyl-2 thio 3 indolinylidene)-propylidene]-benzothiazoline (0.85 g.), 2-

"bromoethanol (0.3 ml.) and chloroform (10'ml.) was re- 'fiuxed for 16 hours." The product obtained by evaporation of the solution was refluxed for minutes in pyridine (10 ml.) with 2-w-acetanilidovinyl-1,3,3-trimethylindoleninium iodide (0.9 g.). Addition ofaqueous potassium iodide solution caused the separation of the dye, which had M. Pt. 204-206", by crystallisation from methanol. 5

EXAMPLE 29.-BIS-(3-METHYL Q 2 BENZOTHIA- ZOLE)B- (.2-2.-HYDROXYETHYLTHIO 1 METH- YL 3 INDOLYL) PENTAMETHINCYANINE BROMIDE (1.0 ml). The solid which separated was collected and crystallised from methanol to yield the dye, M. Pt. 191-- 192".

The dye imparts a new band of sensitivity to a silver "iodobromide photographic emulsion from 6800 to 8500 I V 50 A mixture of 5,6-dimethoxy-3-methyl-2-[2-(l-methyl- A. with a maximumat 8100 A.

Using methods similar to thosedeseribed in Examples 28 and 29, the dyes of Examples 30 to were prepared. These six dyes, the data for which are collected in Table 2, all have the structure of general Formula XI:

7R2 X Y 7 R4 3 l l sornonzon TABLE 2 [The letter following theexample number indicates the merocyanine used. The anion of the salt obtained is indicated in the column of melting point] Sensitislng A. I Example End Groups 1%.,

' Extent Max 30A 3-methyl-2-benzothiazole v3-metliyl-2-benzoxazole 19013191 aiA- do 5,6-dimethoxy-3-methyl-2-ben- 189-192 v6, 900-7, 800 .7, 400

- zothiazole. (I) 3213 3-ethyl-2-benzothiaz0le 3-ethyl-2-benzothiazole 178E181 6,700-1800. 7,200 33G 5,G-dimethoxy-3-methyl-2-ben- 1-methyl-2-quinoline 213-214 l zothiazole. 34G do 3=methyl-2-benzothiazo1e 21(12)12 6.7008,400 1 8,100

. r 351 3,fi-dimethyl-2-benzoselenazole do 14(9B-1)5 6,800.8,300. 8,000

A mixture of 3-methyl-2-[2-(I-phenyLZ-thio-Ii-indolinylidene)propylidene]-benzothiazoline (1.0 g.), :3-iodopropionic acid (0.7 g.) and chloroform (20 ml.) was refluxed for one hour and then evaporated to dryness. The resulting solid and 3-methyl-2-methylthiohenzothiazolium iodide (0.7 g.) were refluxed for one hour with ethanol (20 m1.) and anhydrous sodium acetate (0. 3 -g.). The solid which separated on cooling was collected and crystallised from methanol containing hydriodic acid (8.6. 1.7, 0.2 ml.) to yield the dye as green crystals, M. Pt. 197- 198. (Found: C. 56.5; H, 4.2; I, 16.2; S, 12.8. C H IN O S requires C, 56.9; H, 4.0; I, 16.7; S, 12.7%

The dye extends the sensitivity of a silver iodobromide photographic emulsion to 6550 A. with a 6350 A.

EXAMPLE 37.-ANHYDRO BIS (3 METHYL 2- BENZOTHIAZOLE) 18 (2 2' CARBOXYETI-IYL- THIO 1 PHENYL 3 INDOLYL) -TRIMETHIN- CYANINE HY DROXIDE maximum at A solution of the product from Example 38 in methanol and chloroform (2:1) was run through an ion-exchange column (Deacidite E). The eluate was evaporated to dryness and the residue was crystallised from methanol to yield the dye as deep green crysetals, M. Pt. 203-204; (Found: C, 67.5; H, 5.2; S, 14.3, C H N O S CH O requires C, 67.0; H, 5.0; S, 14.5%.)

p The dye extends the sensitivity of a silver iodobromide photographic emulsion to 6550 A. with a maximum at 6350 A.

EXAMPLE 38. ANHYDRO BIS(6 METHOXY-3- METHYL 2 BENZOTHLAZOLE) 6 (1-METHYL-2- 2. SULPHOEII-IYLTHIO-INDOLYL) -TRIMETH- IN CYANINE HY DROXIDE 6 methoxy-3 -methyl-2-[2-( 1-methyl-2-thio-3-indo1inyl- The mixture extended the sensitivity of a silver iodobromide photographic emulsion to 6550 A. with a maximum at 6350 A.

EXAMPLE 40.(3-E'IHYL-2-BENZOTI-IIAZOLE) (6- ETHOXY 3 ETHYL 2-BENZOTHIAZOLE) 13-(2- CARBOXYMETHYLTHIO 1 ETHYL 3 INDOL- YL) TRIMETHINCYAN]INE IODIDE The method of Example 39 was employed, but using 6-ethoxy-3-ethyl-2-ethylthiobenzothiazolium toluene-p-sulphonate. The product was isolated 'by the addition of aqueous potassium iodide solution and after crystallisation from ethanol had M. Pt. 260-263". It consisted of a mixture of the compound named in the title and that formed by loss of hydrogen iodide, viz. anhydro-(3-ethyl- 2-benzothiazole) (6-ethoxy-3-ethyl-2 benzothiazole) 13-(2 idene)propylidene]-benzothiazoline (0.6 g.), sodium 2- iodoethanesulphonate (0.6 g.) and.2-methoxyethanol (25 ml.) Were refluxed together for 3 hours, and the solution was evaporated to dryness under reduced pressure. The

residue was mixed with 6-methoxy-3-methyl-2-methylthio- .benzothiazolium toluene-p-sulphonate (0.7 g.) and-refiuxed in ethanol (20 ml.) containing triethylamine (0.4

ml.) for one hour. The solid which separated was collected and washed with hot ethanol. Orystallisation from methanol gave the dye as green crystals, M. Pt. '335-336.

(Found: C, 56.4; H, 4.5;S, 18.7. C H N O5S .H O requires C, 56.2; H, 4.9; S, 18.8%.)

The dye extends the sensitivity of a silver iodo bromide" photographic emulsion'to 6150 A'. with a maximum at.

EXAMPLE 39. BIS-(3-ETHYL 2-BENZOTHIAZOLE) Bromoacetic acid DOLYL) -TRIMETHINCYANIN'E BROMIDE acetic acid (0.7 g.) in chloroform (15 ml.) was refluxed for 15 minutes. Evaporation of the solution and washing the residue with dry ether left a red solid, This was re fluxed for 30 minutes in ethanol ('10 ml.) with.13-ethy1-2- ethyl-thiobenzothiazolium toluene-p-sulphonate (1.0 g.)

and triethylamine (0.6 ml.) The solid which separated on diluting the solution with water was collected and. crystallised from ethanol. The product, M. Pt. 1 87-1903, was

a mixture of the dye named in the title with that formed by loss of hydrogen bromide, viz, anhydro-biS-(B-ethyI-Z- benzothiazole) B (2 carboxymethylthiod-ethyl-3-indolyl) -tr -imethineyanine hydroxide.

2-bromoisobutyric acid Sodium 2-iodoetha'nesulphonate j Sodium 4-iodobutanesulphonate Trieth'ylammoniumZ-brbmothyl In most cases the dye was obtained as a mixture with the compound formed from it by loss of HX. For the introduction of the various groups R the following quaternising agents were employed:

Ra -cinema on,

Z-bromopropiom'c acid CH s-bromopropionic acid 3-1od0propionic acid Sodium Z-bromoethanesulphonate The lastof these quaternising agent was prepared by fusing the miethylamine-sulphur trioxide complex (NEt .SO

4.5 g.) with 2-bromoethanol (l.8 ml.) at for 1 /2 hours, cooling and washing theproduct several times with dry ethyl ether.

TABLE 3 [The letter following the example number indicates the merocyanine used. The anion of the salt obtained is indicated in the column of melting points] Sensiti zing 1 1 Example End Groups Ra M 1150,

' Extent Max.

41A 3-methy1-2-b6nz0thiaz01e 3-methy1-2-benzothiazo1e -OH.C02H 2073-208 6,600 6,350

1 r 42A do fin CH2.CH2.COzH 276377 6, 600 6, 350

I /CH3 43A do do OE 202-204 6,600 6,400

COgH /CH3 44A -do -OCO1H 2816282 0,550 6,450

60 -OH2.CH2.SO3H 3465353518 6,550 6,350

, 1' G-methoxy-3-methyl-2- -OHz.CO'zH 203-204 6, 600 6, 400

benzothiazole. (Br) undo -OH2. CH2. C0211 23%;?36 6, 650 6,350

CH3 48A do -C{ I\ 208(310 6, 650 6, 350

49A d0 H.001 OH2.OH2.SO5H 301 1 -3 11 6,600 6,400

r 50A do 5,6-dimethoxy-3-methyl-2- -CH5.005H 212-213 6,650 6,500

' benzothiazole. (Br) I /CHa I OH 208-209 I 6,700 6,1 0 r (I) I 00211. /CHa 52A do G-0 02H 215 216 6,600 6,400

53A do "d0 CHz.CH2-S0sH 26(%2)70 6,750. 6,500

1 54A (10 .6.0 -CH2-CH2-OSO3H 22653-2510 6,700 6,500

r 55B 3-ethyl-2-benzothiazo1e 3-ethy1-2-benz0thiaz01e OH2.0H2.002H 0323 6450 6,350 56B d6 5,6-dim6th0xy-3-methy1-2- -CHz.GH5.CO1H 192-104 6,650 6,550

, benzothiazole. (I) 57B 6 n 3-ethy1-5,6-dimethOxy-2- OH2. CH2- C 02H 154-156 6, 500 6, 150

benzothiazole. (0104) 58B do 3-m6thy1-5,6-methy1ened1oxy-2- OH5.CH2.OO2H 222-226 6,650 ,300 benzotniazole. I (I) 5913 do a-eth l-s,fi-methylenedloxy-Z- CH2.CH2.CO0H 191-193 6,550 200.

. benzothiazole. I (C104) -60D 5-6h1oro-3-methy1-2-benzoth1azole. 5-ch10ro-3-m6chy12-benz0th10z01e. IIGH2.C02H 22535-258 6,450 ,350 61D 10 CH5.O H2.CO5H 220 224 6, 550 6, 350 mu; do 0 I -GH2. H5.S06H 327629 6, 450 6,350 63E 5-methoxy-3-methy1-2- 5-methoxy -3-methy1-2- OH2.CH2.OO5H 266-267 6,800 600 benzothiazole. benzothlazole. (1) 64E do d.o OH2-C'H2-SO3H 35923560 6,700 6,550 65E. dn do CH2JCH2.OSO0H 280E281 6,750 6,550 66F 6-methoxy-3-methyl-2- 6-meth0xy-3-me thy1-2- CH2.OH2.CO2H 188-191 6,700 6,250

benzothiazole. benzothiazole. I (I) 67G 6,6-dimethoxy-3-m6thyl-2 3-methy1-2-benzoth1az01e-.- OH2.CH2.OH2:CH2.SO0H 255-258 6,650 6,500

' benzothiazole. (0104) 68G 6n 5,6-dimethoxy-3-methyl-2- -GH2.COH 230-240 ,800 6,600 Y benzothiazole. (Br) 69G do do OHz. H'2.OOzH 2120 202 6,850 6,600

, r 70G .-do ,OH5.OH1. S05H 35 1 355 1 6,650 6,450

V I 71G do .d0; -CH2.CH2.UH2.CH2.SO3H 6,750 6,000

, 4 72G do -dO -CH2-C 2- 0306 1 2726273 7, 000 6, 800 3-ethy1-5,6- dimeth0xy-2 3-methyl-2-benzothiazo1e.. JH .CH5.BO;H 197-199 6,700 6,350

benzothiazole. (0104) do 5,6-dimethoxy-3-methy1-2- OHz.CH0.C0zH 203-20 6,850 6,550

I benzothiazole. 1 (C101) 00 do -4 CHz.OH2.SOaH 26%;?66 6,850 6,550 .d O L; 5-6th 1-56-0m1e5hoxy-2 -0H5 0112.001H -164 6,650 6,350 benzothiazole. (0104) do dO --CH2.CH2SO6H 6,500 6,300

4 3-2'-hydroxyethy1-2-benzothiazole 3-methyl-2-benzothiazo1e OH2.CH2.CO H 2526256 6,500 6,350 ,...(10 (10 OHz.CI'Iz.SO0H 525 25 6,450 6,300

idene)-propylidene]-benzothiazoline. V r green crystals, M. Pt. 255-256", by crystallisation from 'IIABLE 3-Continued [The letter following the example number indicates the meroeyam'ne used. -The anion of the salt obtained is indicated in the column of melting points] sensitizing .3. Example End Groups Ra Again,

Extent Max.

8m rln 5,6-dim'ethoxy3-methyl-2- CH2.OH2.OO2H 188190 6,450 6,200

, benzothlazole. Sll rln do I CH2.CH2.SO3H 271(373 6,550 6,250 821 3,5-dimethyl-2-benzoselenazole. S-methjl-2-benzothiazo1e.- OH2.0Q2H 216(g18 6,500 6,350 831 when i CH2.CH2.0O2H 209 204 6,650 0,300 841;- do -chloro-3-methyl-2-benzothiazole-. CH2.GH2.CO;H 1922 200 0,450 0,300 851 do fi,tl-diinethoxy-3-methyl-2-,. 411110013 222-224 0,750 6,450

benzothiazole. '(I) 863' dn rln -CH2.GH2.CO2H 19%)200 6, 700 6, 450 871 do 7 0n '-oHz.oH1.so3H 242 45 0,700 0,500 88K 3-ethyl-fi-methyl-2-benzoselenazole 5 ehloro Bethyl-Z-benzothiazole... CHz.CH2.COzH 1776180 6,400 891: do a Bthy1-5edimahOX -2 OH .OH2. 00211 185-187 0, 500 0, 200 benzothiazole. (I)

EXAMPLE 90 m (3 4 METHYL-Z-BENZOTHIAQQ ZOLE) B(2-2'-CARBOXYETHYLTHIO l-METHYL- 3-]NDOLYL)-PENTAMETHINCYANINE IODIDE A mixture of 3-methyl-2[2-'(1-rnethyl-2 thio 3 indo linylidene)-propylidene]-benzothiazoline (0.9 g.) and 3- bromopropionicacidwfi g.) was refluxed in chloroform (20 ml.) for 16 hours.- The productobtained by evapor'ation of the solution todrynes's was refluxed for minutes in ethanol (10 ml.) with 2-w-ethylthiovinyl-3-methylbenzo thiazoli-um toluene-p-sulphonate (1.0 g. and triethylamine (0.4 ml)" Addition of aqueous potassium iodide solution caused the separation of the dye, which formed deep A., withmaxima at 7200 and 8300A.

EXAMPLE 91.(5,6 DIMETHOXY 3METHYL-2- I BENZOTHIAZOLEX 3 METHYL Z-BENZOTHIA- ZOLE) ,B-(22'-CARBOXYETHYLTHIO-1-METHYL 3-INDOLYL) -PENTAMETHINCYANINE IODIDE The dye was prepared as in Exam-pie 90, but usingj5,6- glimethoxy- -3 methyl-2-[2-(1-methyl-2-thio-3:iridolinyl- The dye, formed methanol. t The dye imparts a new band of sensitivity to a: silver iodobromide photographic emiilsionfrom 640010 8500 A. with a maximum'at 8050 A'. A r

EXAMPLE 92.--B'IS -'(3 METHYLJ-BENZO'I'HIA; ZOLE) fi-(1-METHYL-2,2'-SULPHOETHYLTHIOe3- "INDOLYL) -PENTAMETHINCYA-NINE, nnoMinE :A mixture of 3-methyl-2-[2-(l-methyl-Z-thiofidndolinylidene)-propylidene] -benzothiazoline (0.9 g.), sodium 2-bromoethanesulphonate (0.9 g.) and Z-methoxyethanol ml.) was refluxed fo-r 24 hours. The solvent was removed underreduee'd pressure, and the residue and 2-w-ethylthiovinyl-3 -methy lbenzothiazolium toluene-psul- .phonate (1.0 g.) were refluxed together in ethanol .(10

ml.) containing triethylamine ,(0.4 ml.) for 15 minutes. Thesolid which 'separ'ated'wasjcollectjed and crystallised from ethanol to yield the 'dye'as green cfystalsfMJPt.

The dye imparts a new band of sensitivity to a silver iodobromide photographic emulsion from 6700 to 8600 with a maximum at 8100A.

EXAMPLE 93.-(3,4 DIMETHYL-Z-THTAZOLE) (El- A mixture of 3,4 dimethyl-Z-methylthiothiazolium toluene-p-sulphonate (3.35 g.), 3-isopropylidene-methylindolin-Z-thione (2.0 g.), ethanol (20 ml.) and ,triethylamine (1.5 ml.) was refluxed for 2 hours. The solid which separated was collected and washed successively with hot ethanol and hot acetone; 3,4dimethyl-2- [2-(1- methyl v2 thio-3-indolinylidene)-propylidene]-A -thiazoline formed yellow-brown crystals, M. Pt. 212-213" by crystallisation from,v Z-methoxyethanol. .This compound (0.68 g.), methyl-3-iodopropionate (0.6 g.) and chloroform (25 1 ml.) were, refluxed together for 30 minutes. The solid obtained on evaporationgof the solvent was refluxed for one hour in ethanol (20 ml.) with 3 methyl 2-methylthiobenzothiazolium toluene-p-sula phonate (0.9 g.) and triethylamine (0.4 ml.) An aqueous sodium perchlorate solution was added, the dye was extracted .,with chloroform, and the solution was'chromatographed on' an. alumina column. The main purple band was eluted, the eluate was evaporated, and the resulting solid was, washed with light petroleum, to yield the'dye, M. Pt.,-1.12-114. The dye extends the sensitivity of a silver iodobrornide photographic emulsion to 6800 A. with. a maximum at EXAMPLE 94. [3 -METHYLNAPHTHO-(1',2:4,$)471 THIAZOLE] (5,6 DIMETHOXY 3 METHYL-2- BENZOTHIA ZOLE) fi-(2-2f, HYDROXYETHYL l indoIin-Z-thione (2.0 g.), ethanol (20 ml.) and triethylamine (2.0 m1.) Thesolid which separated was collected and washed with boiling methanol; 3-methyl-2- [2 (1 methyl-2-thio-3-indoliny1idene)-propylidene]- naphtho-(1',2':4,5) thiazoline formed bronze-coloured crystals, M. Pt. 298-299" by crystallisation from pyridine. This material (1.4 g.), 2-bromethanol (0.3 ml.) and chloroform ml.) wererefluxed together for hours, and the solution was evaporated to dryness. The product and 5,6-dimethoxy-3-methyl-Z-rnethylthiobenzo- I thiazolium toluene-p-sulphonate (3.0 g.) were refluxed together in ethanol (20 ml.) containing triethylarnine (1.0 ml.) for 30 minutes. Addition of aqueous potassium bromide solution caused the separation ofthe dye, which formed deep purple crystals, M. Pt.'238239, by boiling out with methanol.

The dye extends the sensitivity of a silver iodo-bromide photographic emulsion to 6900 A. with maxima at' 6300 and'670O A.

EXAMPLE 95.(3 METHYL- Z -BENZOTHIAZOLE) (5,6 DIMETHOXY 3-METHYL-2-BENZOTHIA- ZOLE) p 2-2'-HYDROXYETHYLTHIO1l-METH- YL 3 INDOLYL)-ot-METHYLTRIMETHINCY- A ANINE IODIDE A mixture of 2-ethylbenzothiazole (3.3 g.) and methyl toluene-peulphonate (3.8g) was fused at 100 for 3 hours. The product was refluxed in pyridine (20 ml.) with 1-methylindolin-2-thione (3.3 g.).and ethyl orthoacetate (5.0 ml.) for 30 minutes. The product which methyl 2 [1-;-- methyl 2-(1-methyl-2-thio-3-indolinyl- .idene)-propylidene]benzothiazoline formed green crystals,

M. Pt. 257259, by crystallisation from methanol. This material (0.35 g.), 2-bromethanol (021111.) and chloroform ml.) wererefiuxed together for 24 hours,.and

.the solution was evaporated to dryness. The product and -5,6-dimethoxy-3-rnethyl-2 methylthiobenzothiazolium toluene-p-sulphonate (0.45 g.) were refluxed in ethanol (20 ml.) containingtriethylamine (0.2 ml.) for '45 minutes; Addition of aqueous potassium iodide solution caused the separationof the dye, which formed deep blue U crystals, Pt. 208-211", by crystallisation-from meth- I anol.

The dye extends the sensitivity of a silver iodo'bromide photographic emulsion to 6500 A. with a maximum at EXAMPLE 96'. (3-METHYL-2-BENZOTHIAZOLE) (6 -3-METHYL-2-BENZOTHIAZOLE)- [3 (2-2 -CARBOXYETHYLTHIO 5 METHOXY-l- METHYL 3 INDOLYL) TRIMETHINCYANINE PERCHLORATE I I 7 a A mixture of 2,3-dimethylhenzothiazolium toluene-psul'phonate (1.7 g.), 5-1nethoxy-1-methylindolin-2-thione (0.95 g'.), pyridine (10 ml.) and ethyl orthocetate 1.8

ml.) was refluxed for 20 minutes,- and: the mixture was poured'into ethanol. The solid which separated (0.6 g.)

was refluxed with 3-bromopropionic acid "(0.5 g.) .in 2- rnethoxyethanol (10 ml.) for 2 /2 hours. Evaporation of 1 the solvent under'reduced pressure left a redsolid which wasrefluxed for minutes in ethanol (10 ml.) with 6 methoxy-3-methyl-2-methyl-thiobenzothiazoliurn toluenep-sulphonate (1.0 g.) and triethylamine (0.5 ml). Addi= tion of aqueous sodium perchloratesolution caused the The dye extended the. sensitivity of a" silver iodob'romide photographic emulsion to 6450 A. witha maximumat' I EXAMPLE 97. (S-METHYL-Z-BENZOTHIAZOLE)- (5,6 DIMETHOXY 3 METHYL-Z-BENZOTHIA- ZOLE),8 (2 2' CARBOXYETHYLTHIO 5 ME- THOXY 1- METHYL- l-INDOLYL)-TRIMETHIN+ CYANINE PERCHLORATE The dye was prepared similarly to Example 96, and formed purple-brown crystals, M.Pt. 164-165 by crystallisation from methanol.

The dye extended the sensitivity of a silver iodobromide photographic emulsion to 6700 A. with a maximum at '25 separated was collected and washed with hot ethanol; 3-

"What I claim is: 7

1. A cyanine dye selected from the'group consisting of (A) a dye of the formula D; I g --Dg wherein R is selected from the class consisting of alkyl "and aryl, R is alkylene-X wherein X is selected from the group consisting of -COOH, --SO H, OSO H, OH, lower alkoxy, alkanoyloxy, loweralkoxycarbonyl, -CN, amino, lower alkyl amino and carbomyl, R is selected from the class consisting of hydrogen and alkyLR and R are each selected from the class consisting of alkyl, hydroxyalkyl where the alkyl moiety contains 1 to' 6 carbon atoms and aralkyl where the alkyl moiety contains 1 to 6;carbon atoms, m; i and 11 are each selected from nought and one, Xis an acid radical, Y is selected from the class consisting of hydrogen and lower alkoxy and D .and D each'represent theatoms necessary to complete the heterocyclic nucleus selected from the group consisting of a thiazole nucleus, benzothiazole nucleus, naphthothiazole nucleus, b enzoxazole nucleus,'naphthoxazole nucleus, 1 benzoselenazole nucleus, pyridine nucleus, quinoline nuseparation of the dye, which formed bronze-coloured crys- V I tals, M.Pt. 175-176", from methanol.

' cleus, I a-naphthoquinoline nucleus, fi-naphthoquinoline nucleus, indolenine nucleus, diazole' nucleus, thiazoline nucleus and diazine nucleus; (B) corresponding dyes of the-said formula but in which the X radical in a hydrogen atom of an acid group containedin R are eliminated;

. and (C) corresponding'acid addition salts of those of the [3+ 1-methyl-2 2'-sulphoethylthio-3-indolyl) -trirnethin cyanine hydroxide. i '8. (3,4 dimethyl 2 thiazole) (3-methyl-2-b enzothia zole.) [3-(2-2-methoxy carbonylethylthio 1 methyl-3-indolyl) -trimethincyanine perchlorate. j

'9. Bis (3-methyl-2-benzothiazole),8-(2-2carboxyethylthio-1-methyl-3-indolyl)-pentamethincyanine iodide; I 10'. (3-rnethyl-2-benzothiazole') (5,6- dimethoxy-3-methy 1 2-benzothia'zole) B-( 1-rnethyl-2-2Qsulphoethylthio-3 -in- 'd IyD-trimethincyanine bromide.

11.. ,Bis-( 5,6-dimethoxy-3 methyl-2-benzothiazole 8- 2- 2'v carbamoyl-ethylthio-1+methy1-3 -indolyl trimethincyanineiodide. 1 1 '3 References Cited by the Examiner UNITED STATES PATENTS 2,921,067 1/60 Larive et al. 1 260-24065 2,961,318 11/60. Jones 96104 (Gther references on following page) 17 1 FOREIGN PATENTS Welch et aL: Science, volume 105, pages 486-488 845,588 8/60 G tB 't (1947).

Tea n am Peters et aL: J. Pharm. and Exptl. Therapy, volume 95, OTHER REFERENCES pages 212, 215 CO 217 and 23210 233 1949).

Venkataraman: The Chemistry of Synthetic Dyes, 5 volume 11, pages 1153, 1166 and 1185 [0 1186, Academic IRVING MARCUS, Prlmary Examiner- Press 1952 (New J. D. RANDOLPH, WALTER A. MODANCE,

Examiners. 

1. A CYANINE DYE SELECTED FROM THE GROUP CONSISTING OF (A) A DYE OF THE FORMULA 